I’ve got the same problem: Whenever I try to access a page from the backend it shows an error 500 after updating Yoast SEO to version 3.3.4.
Tried your suggestion, neotrope, didn’t work.
For now I’ll just leave it deactivated as I don’t have time to debug this right now, I find it hard to believe that there is an issue with my theme as I’m using the latest version of Divi.
Any other possible solutions are welcome..